Peptide pores in lipid bilayers : voltage facilitation pleads for a revised model

TL;DR

This paper revises the existing model of peptide-induced pore formation in lipid bilayers by incorporating electric field effects, supported by new experiments, to better explain voltage and temperature dependence of pore opening.

Contribution

It introduces a new model accounting for electric field-induced tension differences and lipid translation entropy cost in pore formation, challenging previous theories.

Findings

Electric field causes unbalanced tension in bilayer leaflets.

Pore opening entropy cost is mainly due to lipid excluded-area.

Experimental data support the revised model.

Abstract

We address the problem of antimicrobial peptides that create pores in lipid bilayers, focusing on voltage-temperature dependence of pore opening. Two novel experiments (voltage-clamp with alamethicin as an emblematic representative of these peptides and neutron reflectivity of lipid-monolayer at solid/water interface under electric field) serve to revise the only current theoretical model (H. W. Huang et al.Phys. Rev. Lett., 92, 198304 (2004)). We introduce a general contribution of the electric field as being responsible for an unbalanced tension of the two bilayer leaflets and we claim that the main entropy cost of one pore opening is due to the corresponding "excluded-area" for lipid translation.